Work vehicles such as, for example, motor graders, backhoe loaders, agricultural tractors, wheel loaders, skid-steer loaders, and other types of heavy vehicles are used for a variety of tasks requiring operator control of the work vehicle and various work implements associated with the work vehicle. These work vehicles and work implements can be relatively complicated and difficult to operate. They may have an operator interface with numerous controls for steering, position, orientation, transmission gear ratio, and travel speed of the work vehicle, as well as position, orientation, depth, width, and angle of the work implement.
Historically, work vehicles have incorporated single-axis lever control mechanisms with complex mechanical linkages and multiple operating joints, or a plurality of cables to provide the desired functionality. Such control mechanisms require operators with high skill levels to control the many input devices. After a period of operating these control mechanisms, the operators may become fatigued. In addition, because the operator's hand may be required to travel from one actuating element to another, an operator's delayed reaction time, as well as the complexity and counter-intuitiveness of the controls, may result in poor quality and/or low production.
An operator interface may include a control handle control mechanism designed to reduce operator fatigue, improve operator response time, and facilitate functionality of the work vehicle. For example, U.S. Pat. No. 5,042,314 (the '314 patent), discloses a steering and engine speed control mechanism that includes a transversely rockable control handle. The steering and engine speed control mechanism also includes a steering actuator element connected at the bottom of the control handle to depress either a left or right actuating plunger of a hydraulic pilot valve assembly for effecting steering. The steering and engine speed control mechanism further includes an electrical switch activating element which is used to select one of the transmission gear speed ratios of a multi-speed transmission through an associated electronic control mechanism.
Although the steering and engine speed control mechanism of the '314 patent may alleviate some of the problems associated with separate work vehicle controls for effecting steering and select transmission operations, the throttle control is still operated via a mechanical hand or foot operation which is separate from the steering and control mechanism described. The operator must take his/her hand off the vehicle control lever in order to adjust the throttle, thereby creating safety and worker fatigue issues during operation of the vehicle.
It would therefore be beneficial to provide a mechanism which is controlled by the hand of the operator and from which the throttle can be controlled to minimize operator fatigue and enhance safety.